They could simply make it by combining oxygen and hydrogen... for much cheaper than sending millions of troops across billions of kms and then deal with resistance.
or any of the other abundant minerals, etc, found on our planet.
Same as water - just with different atoms.
Or the simple fact that since our planet is life-bearing that it may (just may) be tolerable in some capacity for alien life.
Yes, but there are a lot of land in other planets and can be terraformed for much cheaper than sending millions of troops across billions of kms.







